Snorkel with pump

ABSTRACT

The instant invention is a skin diving snorkel having a conduit with an open end above the water surface, and an underwater end which terminates in a collapsible chamber. A mouthpiece adjacent and above the chamber provides a flow path between the conduit and the interior of the diver&#39;s mouth. A check valve in the opening between the conduit and the chamber allows water to flow from the conduit into the chamber, but not in the reverse direction. The chamber also has a purge valve which allows water in the chamber to flow to ambient. When the hydrostatic pressure within the snorkel is greater than ambient, water will flow sequentially through the check valve, chamber and purge valve to ambient. Consequently, water in the snorkel which extends above the ambient water surface will ultimately drain through the purge valve, decreasing the amount of water remaining within the snorkel to be purged. The chamber volume and double valve arrangement inhibit the flow of air through the purge valve during a purging exhalation, minimizing the wasteful loss of purging air. The chamber can be manually or mechanically collapsed, which reduces the chamber&#39;s internal volume. Collapsing the chamber will force air or water within to flow out the purge valve. When the collapsing force is removed, a spring, or alternately, the resilient construction of the chamber itself, will cause the chamber to expand back to its original internal volume. The expanding chamber will pull water from the conduit through the check valve into the chamber. Alternately collapsing and expanding the chamber will pump water from the conduit to ambient without resorting to an explosive exhalation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally related to snorkels used by skindivers. More particularly, this invention is concerned with purgingwater from a flooded snorkel.

2. Description of the Prior Art

Skin divers use the snorkel as a means to breathe while swimming facedown the water surface. The snorkel functions as a conduit between thediver's mouth and the overhead air. Typically, when in use, the open endof the snorkel conduit extends a short distance above the water surface.Occasionally, due to swimming movements or wave action, small amounts ofwater flow into the open end of the snorkel and partially flood theconduit. Also, water will flood the snorkel when the diver swims ordives below the water surface. An experienced skin diver can sense whenwater enters the snorkel and responds by immediately stoppinginhalation. Respiration is resumed after the snorkel has been purged ofwater.

Inexperienced skin divers find occasional flooding especiallytroublesome because, undetected, water can be inhaled resulting incoughing and extreme discomfort. Consequently, several configurationshave been proposed to restrict or block the normally open end of thesnorkel and thereby prevent water from entering.

U.S. Pat. No. 2,317,236 entitled Breathing Apparatus for Swimmers,issued to C. H. Wilen, et al, on Apr. 20, 1943, teaches a valve with abuoyant ball arranged to block the above water end of the snorkelwhenever water starts to enter. Such valves are bulky, often fail toseal, and, also, significantly increase respiratory effort. Althoughonce popular, such devices are now considered unreliable and obsolete.

A recent invention functionally similar to the snorkel of Wilen, U.S.Pat. No. 5,117,817 entitled Vertical Co-Axial Multi-Tubular DivingSnorkel, issued to Hsin-Nan Lin on Jun. 2, 1992 teaches an annular floatarrangement which blocks the above water end of the snorkel wheneverwater starts to enter. To assist in purging, the Lin snorkel alsoincorporates a secondary purge tube within the breathing conduit. TheHsin-Nan Lin snorkel suffers from the same problems as the Wilensnorkel.

U.S. Pat. No. 4,071,024 entitled Snorkel, issued to Max A. Blanc on Jan.31, 1978, teaches an air entrapping cap which is mounted on the abovewater opening of the snorkel. A tortuous passage in the cap retardswater flow into the snorkel. Although such a cap is somewhat effectivein blocking the occasional flow of surface water into the snorkel, italso retards expulsion of water which enters the snorkel during a diveor swim below the water surface. The significant increase in respiratoryand purging effort limits its utility and subsequent popularity.

Similar to Blanc, U.S. Pat. No. 5,199,422 entitled Modular Snorkel,issued to Stan Rasocha on Apr. 6, 1993, teaches an exhaust valve mountedon a cap which covers the upper end of the snorkel. The cap restrictsthe entry of splashed water into the snorkel. The exhaust valve on thecap permits the expulsion of water from within the snorkel during apurging exhalation. Rasocha's snorkel increases respiratory effort anddoes not noticeably reduce purging effort.

The open snorkel conduit will be completely flooded with water when askin diver returns to the surface after swimming or diving underwater.The open end of the snorkel is above the water when the skin diver swimsface down on the water surface. With the open end of the snorkel abovethe water, the conduit is purged for respiration by exhaling anexplosive blast of air into the mouthpiece.

Surface tension forms the purging blast of air into a bubble which spansthe cross section of the conduit. Pressure within the bubble expands thebubble toward the open end of the snorkel conduit. As the leadingsurface of the bubble moves away from the mouthpiece, the bulk of thewater within the conduit is pushed ahead of the bubble and out the openend.

The purging bubble of air will slip past water which adheres to theinside surface of the conduit. After the purging air bubble is spent,residual water will flow down the inside surface toward the mouthpiece.Also, water which splashes into the open end of the snorkel conduit dueto swimming movements or wave action will typically strike and adhere tothe inside surface of the conduit and thereafter flow toward themouthpiece. Water accumulates at the lowermost portion of the snorkelconduit, typically adjacent the mouthpiece, and soon obstructs theconduit. Unless the conduit is completely blocked, a slow and cautiousinhalation is possible after which another purging exhalation can bemade.

The respiratory effort needed to purge a snorkel is significant. Manyskin divers lack the respiratory strength needed to completely purge aflooded snorkel with a single exhalation, and must repeat the purgingprocedure several times. Also, water will sometimes enter the snorkeljust as the diver has completed an exhalation, leaving very little airin the lungs to satisfactorily complete a purge. Consequently, a meanswhich decreases the respiratory effort and the amount of air required topurge a snorkel will be very beneficial.

A popular solution places an externally directed purge valve in the wallof the snorkel conduit at a location near the snorkel mouthpiece. Waterin the flooded conduit which extends above the ambient water surfacewill drain through the purge valve. Because the total volume of water inthe flooded snorkel is reduced by water flow through the purge valve,the respiratory effort required to purge the remaining water is alsoreduced.

Unfortunately, a purge valve also provides an alternate path forforcefully exhaled air. A purge valve located close to the mouthpiecewill quickly and wastefully dissipate the explosive blast of purgingair. One solution to this problem places the purge valve at a locationapproximately midway between the mouth opening and the open end of thesnorkel conduit.

At mid-length of the snorkel conduit, the purge valve will be close tothe ambient water surface when the skin diver is swimming face down onthe water surface. At such a location, the purge valve will drain thatportion of the snorkel conduit which extends above the water surface,but will not initially interfere with the purging blast of air. Even atthis location, the purge valve will dissipate the forcefully exhaled airand the amount of residual water adhering to the inner surface of theconduit between the purge valve and the open end will be substantial.The residual water subsequently accumulates at the lowermost portion ofthe snorkel conduit and obstructs the conduit. Consequently, the purgevalve by itself, even when located mid-length of the snorkel conduit, isof limited benefit.

U.S. Pat. No. 4,278,080 entitled Diving Snorkel, issued to Joseph N.Schuch on Jul. 14, 1981, teaches a purge valve located at the bottom ofa branch conduit which joins the snorkel conduit at a locationapproximately midway between the mouthpiece and the open end. The purgevalve drains the snorkel conduit until the water level within theconduit matches the ambient water level. Part of the purging air willdivert into the branch conduit and force water within the branch conduitout the purge valve. Schuch teaches that the branch conduit must havesufficient length to provide the transient resistance necessary to allowpurging of the snorkel conduit before the purging air reaches and isdissipated by the purge valve.

Water within the snorkel conduit of Schuch is pushed out the open endbefore the purging air clears the branch conduit of water and reachesthe purge valve. Nevertheless, diverting part of the purging bubble ofair into a branch conduit abates the driving pressure within the purgingbubble and allows significant residual water to adhere to the upperportion of the snorkel conduit. Consequently, although the snorkelconfiguration of Schuch somewhat reduces the effort required to purge aflooded snorkel, it does not decrease the amount of purging airrequired, and it does not reduce residual water which adheres to thesnorkel conduit wall and soon flows down the wall to obstruct thesnorkel conduit near the mouthpiece. Also, the branch conduit addssignificantly to the size of the snorkel, making the snorkel unwieldy inuse.

As another approach, U.S. Pat. No. 5,143,059 entitled Water Trap for aSnorkel, issued to John Delphia on Sep. 1, 1992, teaches a water trapadjacent a purge valve located approximately mid-length on the snorkel.Water flowing within the snorkel is deflected and retained untildischarged through the exhaust valve. The trap means of Delphia is acomplex combination of baffles, lips and openings which inherentlyrestrict respiratory flow and require relatively complex tooling formanufacturing.

In view of the foregoing factors, conduits and problems which arecharacteristic of the prior art, the applicant has invented and patentedseveral improved snorkels.

The first improved snorkel is taught by the applicant's application Ser.No. 107,987 filed Oct. 13, 1987 now U.S. Pat. No. 4,879,995 which issuedNov. 14, 1989. The improved snorkel includes a conduit whose length isdivided by a chamber located above the water surface when the snorkel isin the approximate position of use by a skin diver swimming face down onthe water surface. A flared transition from the inside cross section ofthe upper conduit to the larger inside cross section of the chamber issmooth and continuous. A chamber purge valve initially drains thechamber and upper conduit of water when the skin diver returns to thesurface after swimming or diving underwater. The lower conduit is purgedfor respiration by exhaling a forceful blast of air into the mouthpiecewhich pushes the water upward. The effort required to purge the improvedsnorkel is reduced because the bulk of the ascending water flows out thechamber purge valve, without the need to overflow the snorkel top. Aftera purging procedure, or after splashing into the open end of the upperconduit due to swimming movements or wave action or the like, the forcesof molecular cohesion and adhesion cause water to flow down the insidesurface of the upper conduit and chamber to the chamber purge valve. Thepurge valve opens under slight hydrostatic pressure and drains the waterto ambient at a rate sufficient to prevent overflow into the lowerconduit. In an alternate configuration, taught by the applicant'sapplication Ser. No. 420,278 filed Oct. 12, 1989 now U.S. Pat. No.5,092,324 which issued Mar. 3, 1992, initial drainage is facilitated bya second purge valve located at the bottom of a second chamber below themouthpiece. The second chamber also serves to capture drainage from themouthpiece and water which overflows from the upper conduit.

A third improved snorkel is taught by the applicant's application Ser.No. 292,224 filed Dec. 30, 1988 now U.S. Pat. No. 4,872,453 which issuedOct. 10, 1989. The improved snorkel features a chamber that intersectsthe conduit at a location that is at approximately mid-length. Thechamber houses a float member. When water fills the snorkel, the floatmember is buoyed out of the chamber into the conduit and blocks upwardflow therein. The flooded snorkel is purged by exhaling into themouthpiece. Because the float member blocks upward flow when the conduitis flooded, the upwardly expanding exhaled air is trapped beneath thefloat member. The trapped air displaces the water in the conduit,forcing the water down and out the purge valve. As a consequence, theeffort and amount of air required to purge the Christianson snorkel aresignificantly reduced.

A fourth improved snorkel is taught by the applicant's application Ser.No. 292,225 filed Dec. 30, 1988 now U.S. Pat. No. 4,877,022 which issuedOct. 31, 1989. The improved skin diving snorkel has a conduit with anunobstructed, open end above water and an underwater end whichterminates in a chamber. The chamber houses a normally closed floatvalve in series with an outwardly directed purge valve. The purge valveallows water in the snorkel to flow to ambient when hydrostatic pressurewithin the snorkel is greater than ambient. The chamber also serves toaccumulate water which drains down the conduit after a purgingexhalation or after splashing in the open end. A mouthpiece adjacent andabove the chamber provides a flow path from the conduit to the interiorof the diver's mouth. The float valve opens when the chamber is floodedwith water. Consequently, water in the snorkel which extends above theambient water surface will drain through the purge valve, decreasing theamount of water remaining within the snorkel to be purged. The floatvalve blocks flow through the purge valve when the chamber is emptied ofwater during a purging exhalation, preventing the wasteful loss ofpurging air. Water which accumulates in the chamber between purges iseliminated when the snorkel is next purged.

The instant invention is yet another improved snorkel. The instantsnorkel provides a means to pump residual water from the interior of thesnorkel without the need for a purging exhalation. In addition, the pumphinders the wasteful loss of purging air through the purge valve.

SUMMARY OF THE INVENTION

The instant invention is a skin diving snorkel having a conduit with anopen end above the water surface, and an underwater end which terminatesin a collapsible chamber. A mouthpiece adjacent and above the chamberprovides a flow path between the conduit and the interior of the diver'smouth. A check valve in the opening between the conduit and the chamberallows water to flow from the conduit into the chamber, but not in thereverse direction. The chamber also has a purge valve which allows waterin the chamber to flow to ambient. When hydrostatic pressure within thesnorkel is greater than ambient, water will flow sequentially throughthe check valve, chamber and purge valve to ambient. Consequently, waterin the snorkel which extends above the ambient water surface willultimately drain through the purge valve, decreasing the amount of waterremaining within the snorkel to be purged. The chamber volume and doublevalve arrangement inhibit the flow of air through the purge valve duringa purging exhalation, minimizing the wasteful loss of purging air. Thechamber can be manually or mechanically collapsed, which reduces thechamber's internal volume. Collapsing the chamber will force air orwater within to flow out the purge valve. When the collapsing force isremoved, a spring, or alternately, the resilient construction of thechamber itself, will cause the chamber to expand back to its originalinternal volume. The expanding chamber will pull water from the conduitthrough the check valve into the chamber. Alternately collapsing andexpanding the chamber will pump water from the conduit to ambientwithout resorting to an explosive exhalation.

DESCRIPTION OF THE DRAWINGS

A detailed description of the invention is made with reference to theaccompanying drawings wherein like numerals designate correspondingparts in the several Figures.

FIG. 1 is a front elevation view of a snorkel which has been constructedin accordance with the principles of the instant invention, and which ispictured in the approximate position of use by a skin diver swimmingface down on the water surface.

FIG. 2 is a longitudinal sectional view of the snorkel of FIG. 1, shownduring respiration.

FIG. 3 is a partial sectional view of the snorkel of FIG. 2, taken alonga plane corresponding to line 3--3 of FIG. 2.

FIG. 4 is a view similar to FIG. 2, showing the snorkel flooded withthat portion above the water surface draining to ambient.

FIG. 5 is a view similar to FIG. 2, showing the snorkel during a purgingexhalation.

FIG. 6 is a view similar to FIG. 2, showing the snorkel being purged bypumping.

FIG. 7 is a partial view of the snorkel of FIG. 2 showing an alternatepumping action.

FIG. 8 is a partial view of the snorkel of FIG. 2 further showing thepumping action.

FIG. 9 is a view similar to FIG. 2, showing an alternate configuration.

FIG. 10 is a partial view showing another configuration.

FIG. 11 is a partial view showing yet another configuration.

FIG. 12 is a partial view of the snorkel of FIG. 11, showing the snorkelbeing purged by pumping.

FIG. 13 is a view similar to FIG. 2, showing yet another alternateconfiguration.

FIG. 14 is a partial view of the snorkel of FIG. 13, showing the snorkelbeing purged by pumping.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description is of the best presently contemplatedmodes of carrying out the invention. This description is not to be takenin a limiting sense, but is made merely for purposes of illustrating thegeneral principles of the invention.

Referring to FIGS. 1 and 2, snorkel 10 is pictured in the approximateposition of use by a skin diver swimming face down on the water surface.(For clarity, the diver is not pictured in the FIGS.) Snorkel 10includes conduit 12 having an upper end with opening 14. Conduit 12 isconstructed of a rigid or semi-rigid material, for example, vinylplastic or the like. The upper end of conduit 12 extends into the airabove ambient water surface 16. Air and water can freely enter and exitconduit 12 because opening 14 is not obstructed and provides fluid flowthere through with little or no resistance.

The lower end of conduit 12 is attached to chamber 18. The openingbetween conduit 12 and chamber 18 is closed by check valve 20.

Check valve 20 is oriented to allow water to freely flow from conduit 12into chamber 18. Check valve 20 is, typically, a flexible diaphragm of aresilient material, for example silicon elastomer or the like, which isrestrained in such a way that it can selectively flex under slightpressure to allow flow in one direction only. Reverse pressure forcesthe diaphragm to seal closed. Consequently, check valve 20 will preventthe reverse flow of water from chamber 18 into conduit 12.

Mouthpiece 22, above check valve 20, branches from the side of conduit12. Mouthpiece 22 opens upward. Mouthpiece 22 is adapted to be held bythe mouth of the diver and provides a flow path from conduit 12 to theinterior of the mouth. (In the FIGS., the opening of mouthpiece 22should be considered covered by the diver's mouth.) The intersection ofmouthpiece 22 with conduit 12 forms an approximately elliptical opening24 (as shown best in FIG. 3).

Conduit 12 is configured to approximately match the curvature of thediver's head. The upper portion of conduit 12 curves smoothly to placeopening 14 approximately over the center of the head. Alternately, theupper portion of conduit 12 can be straight.

Respiration and purging are facilitated by providing a substantiallysmooth flow path which is free of abrupt changes in path direction.While not so limited, the curvature may, the example, follow anelliptical path.

In one embodiment of the instant invention, wall 26 of chamber 18 isconstructed of a resiliently flexible material, for example, moldedneoprene rubber. For increased flexibility, wall 26 can incorporateconvolutions 28. Alternately, wall 26 can be without convolutions (forexample, as shown in FIG. 10). The resiliency of the material serves toforce the walls of chamber 18 to return to their original shape orposition after being distorted due, for example, to being squeezed bythe diver's hand.

Purge valve 30 closes an ambient opening in chamber 18. Purge valve 30is oriented to allow water to freely flow from chamber 18 to ambient.Purge valve 30 is, typically, a flexible diaphragm of a resilientmaterial, for example silicon elastomer or the like, which is restrainedin such a way that it can selectively flex under slight pressure toallow flow in one direction only. Reverse pressure forces the diaphragmto seal closed. Consequently, purge valve 30 will prevent the reverseflow of water from ambient into chamber 18.

When a skin diver swims or dives below the water surface, water willpour into conduit 12 through opening 14, flooding the snorkel. After theskin diver surfaces and assumes the face down, surface swimmingattitude, hydrostatic pressure will cause water (depicted as havingsurface 16a in FIG. 4) within the upper portion of snorkel 10 to flowdownward through check valve 20 into chamber 18, increasing the pressurewithin chamber 18. The increased pressure within chamber 18 will causethe water within chamber 18 to flow through purge valve 30 to ambient.Referring to FIG. 4, the outflow of water (depicted as solid arrows) hasflexed both check valve 20 and purge valve 30 outward.

After surface 16a drops to the level of ambient surface 16, waterremaining in conduit 12 is purged by forcefully exhaling air intomouthpiece 22 (depicted as a large outline arrow in FIG. 5). Referringto FIG. 5, surface tension forms the exhaled air into a bubble havingsurface 16b which expands upward in conduit 12. As the leading surfaceof the bubble moves away from mouthpiece 22, the bulk of the waterwithin conduit 12 is pushed ahead of the bubble and forced out opening14 (depicted as solid arrows).

Referring again to FIG. 5, a forceful exhalation will also expanddownward against water surface 16a. The pressure against surface 16awill force the water below mouthpiece 22 to flow sequentially throughcheck valve 20, chamber 18, and purge valve 30. The purging exhalationtherefore forces water within conduit 12 to be cleared both above andbelow mouthpiece 22. As a benefit, the internal volume of chamber 18 andthe double valve arrangement provide the transient resistance necessaryto allow purging of snorkel conduit 12 before the purging air reachesand is dissipated by the purge valve.

Water which splashes into opening 14, due to swimming movements or waveaction or the like, will accumulate in conduit 12 above check valve 20.Similarly, fluids from the mouth, and residual water which adheres tothe inner surface of conduit 12 after a purging exhalation, willaccumulate above check valve 20 as depicted by surface 16a in FIGS. 6, 7and 8. If chamber 18 is free of water, some of the water accumulatingabove check valve 20 will flow through check valve 20 into chamber 18.However, ambient hydrostatic pressure against purge valve 30 willprevent continued drainage from chamber 18 to ambient.

The volume of the section of conduit 12 between mouthpiece 22 and checkvalve 20, combined with the internal volume of chamber 18, isadvantageously sized to hold residual water which remains after apurging exhalation and also small amounts of water which occasionallysplash into opening 14. Referring to FIGS. 6, 7 and 8, even though somewater has accumulated below mouthpiece 20, respiratory flow remainsunimpeded. Empirical studies have determined that a combined volumeequivalent to ten percent (10%) of the snorkel's total internal volumeis sufficient for this purpose.

Referring again to FIG. 6, wall 26 of chamber 18 is shown flexed orpinched inward, thereby reducing the internal volume of chamber 18.Reducing the internal volume of chamber 18 forces at least part of theair or water within chamber 18 to flow out purge valve 30 to ambient. InFIG. 6, the outflow of water (depicted as solid arrows) has flexed purgevalve 30 outward. The force (depicted as outline arrows in FIG. 6) whichflexes wall 26 inward can be applied by the diver's fingers or hand.

Depicting another way to reduce the internal volume of chamber 18, FIG.7 shows the internal volume of chamber 18 reduced by forcingconvolutions 28 of wall 26 to be collapsed by an axially directed push(depicted as an outline arrow in FIG. 7).

Referring to FIG. 8, when the collapsing force is removed, theresiliency of wall 26 will force chamber 18 to expand back to itsoriginal internal volume. The expansion will pull water or air fromconduit 12 through check valve 20 into chamber 18. In FIG. 8, the flowof water (depicted as solid arrows) from conduit 12 into chamber 18 hasflexed check valve 20 into chamber 18.

By alternately contracting and releasing chamber 18, residual water canbe pumped from conduit 12 without the need for a purging exhalation.While not so limited, the pumping force is manually applied by thediver's hand or fingers. Alternately, the pumping force can be generatedelectro-mechanically by utilizing appropriate batteries, motors andcontrol circuits.

The orientation of chamber 18 can be in any direction relative toconduit 12 or mouthpiece 22. For example, FIG. 9 shows an orientationwhich is at 90° to the longitudinal axis of conduit 12. Ideally, chamber18 will be oriented to minimize the frontal area of the snorkel when thediver is swimming through the water.

The size and shape of chamber 18 can be any one of a number of shapes orconfigurations. For example, FIG. 10 shows chamber 18 as having abulb-like shape.

Chamber 18 does not need to be fabricated of a flexible material. FIG.11 shows chamber 18a configured as rigid or semi-rigid position 32having return spring 34. Check valve 20 is housed within a shortextension of conduit 12 adjacent mouthpiece opening 24. Purge valve 30is advantageously mounted on piston 32. Chamber 18a is defined by thevolume between check valve 20 and purge valve 30.

The configuration of FIG. 11 will require the use of appropriate dynamicseals and movement limiting stops. However, the dynamic seal betweenpiston 32 and the mating surface of conduit 12 does not have to beabsolutely water tight. For ease of movement, position 32 can beconfigured to have a small circumferential clearance with the matingsurface of conduit 12. The amount of water leaking past piston 32 willbe relatively insignificant when compared to the amount of water pumpedby the movement of piston 32. Furthermore, ambient water which leakspast piston 32 into chamber 18a will be prevented from entering conduit12 by check valve 20.

Referring to FIG. 12, the internal volume of chamber 18a has beenreduced by the inward axial movement of piston 32. As a consequence ofthe inward axial movement of position 32, spring 34 is compressed. Thecompressing force (depicted as an outline arrow in FIG. 12) which movespiston 32 inward is typically applied by the diver's fingers or hand.

When the compressing force is removed, spring 34 will force piston 32outward, thereby re-expanding chamber 18a to its original internalvolume. Similar to the action depicted by FIG. 8, as chamber 18are-expands, water or air will be pulled from conduit 12 through checkvalve 20 into chamber 18a. The alternating reduction and recovery of theinternal volume of chamber 18a produces a pumping action which removeswater from the interior of conduit 12.

FIGS. 13 and 14 show the preferred configuration. The inventive snorkelconfiguration of FIG. 13 incorporates internal piston 42 and associatedspring 44 housed within rigid or semi-rigid extension 12' of conduit 12.As shown in FIG. 13, spring 44 is a compression spring located withinchamber 18b. Alternately, spring 44 can be a tension spring attached atone end to the conduit side of piston 42, and having the other endappropriately anchored to the inside wall of conduit 12. Whethercompression or tension, spring 44 serves to provide the force whichselectively returns piston 42 to the position which provides the maximumvolume of chamber 18b.

For the configuration of FIG. 13, check valve 20 is advantageouslymounted on, and carried by, piston 42. Purge valve 30 is mounted tocover the end of extension 12'. Chamber 18b is defined by the volumebetween check valve 20 and purge valve 30.

The configuration of FIG. 13 requires the use of appropriate dynamicseals and movement limiting stops. However, the dynamic seal betweenpiston 42 and the inside mating surface of extension 12' does not haveto be absolutely water tight. For ease of movement, piston 42 can beconfigured to have a small circumferential clearance with the matinginside surface of extension 12'. The amount of water leaking past piston42 will be relatively insignificant compared to the amount of waterpumped by the movement of piston 42. Furthermore, purge valve 30 willprevent ambient water from entering chamber 18b and subsequently flowinginto conduit 12.

Movement of piston 42 is facilitated by pull-rod 46. Knob 48, on the endof pull-rod 46, provides a firm place for the fingers to grip whenpulling pull-rod 46. Alternately, pull-rod 46 can be a flexible cable,or the like, and knob 48 can be a ring, or the like. The pulling forceis depicted as an outline arrow in FIG. 14.

Referring to FIG. 14, pull rod 46 has been pulled outward thereby movingpiston 42 and check valve 20 toward purge valve 30. Consequently, theinternal volume of chamber 18b is reduced and spring 44 is compressed.When the pulling force is removed, spring 44 will force piston 42upward, thereby re-expanding chamber 18b to its original internalvolume. Similar to the action described supra, alternately pulling andreleasing pull rod 46 produces a pumping action which removes water fromthe interior of conduit 12.

Other variations on the diameter, cross-section shape and radius ofcurvature of the conduit; various splash blocking structures andcoverings of opening 14; various shapes and configurations of chamber18, the use of multiple chambers, and various methods to adjust themouthpiece or chamber location relative to the conduit, arecontemplated. It is understood that those skilled in the art mayconceive of modifications and/or changes to the invention describedabove. Any such modifications or changes which fall within the purviewof the description are intended to be included therein as well. Thisdescription is intended to be illustrative and is not intended to belimitative. The scope of the invention is limited only by the scope ofthe claims appended hereto.

I claim:
 1. A snorkel device comprising:a conduit having first andsecond open ends thereof; said conduit first open end adapted to admitambient fluid into said conduit; mouthpiece joined to said conduitbetween said first and second open ends for communicating fluid flowwith said conduit; pump connected to said conduit second open end, saidpump arranged to selectively provide unidirectional flow of fluid fromsaid conduit for evacuating fluid from said conduit; said pumpcomprising a unitary chamber having walls with first and second openingsthereof; said chamber first opening joined to communicate fluid flowwith said conduit second open end; purge valve adjacent said chambersecond opening, said purge valve arranged to selectively provideunidirectional flow from said chamber to ambient; piston situated withinsaid chamber, said piston slidablely engaged with said chamber walls,said piston capable of reciprocating motion between said chamber firstand second openings; said piston incorporates a check valve, said checkvalve arranged to selectively provide unidirectional fluid flow fromsaid conduit to said chamber; forcing means associated with said pistonto selectively position said piston adjacent said chamber first opening;and control means attached to said piston to allow the user toselectively counter said forcing means for expelling fluid to ambientthrough said purge valve.
 2. The snorkel device recited in claim 1wherein:said forcing means is a spring.
 3. The snorkel device recited inclaim 1 wherein:said control means is manually operated.
 4. The controlmeans recited in claim 3 wherein:said control means is a pull-rod.